js4py: source/functions.rst annotate

annotate source/functions.rst @ 162:77e87f1b5811 core-javascript

$ hg merge core-javascript.closure-exercises # done, at least for now

author	jf3243
date	Wed, 09 Nov 2011 17:00:38 +0000
parents	b76dbf891f88
children	4e6cfa066d1a

rev	line source
6 5a1388541f50 index.rst: Added links to some stub pages. Jonathan Fine <jfine@pytex.org> parents: diff changeset	1 Functions
5a1388541f50 index.rst: Added links to some stub pages. Jonathan Fine <jfine@pytex.org> parents: diff changeset	2 =========
11 ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	3
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	4 A function contains code, possibly with parameters, that is stored for
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	5 later use. In both JavaScript and Python, functions are first-class
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	6 objects. This means that identifiers can have a function as their
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	7 value, and be used as the parameter or return value of a function.
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	8
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	9 It's common, when writing JavaScript for web pages, to create a large
12 4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	10 number of anonymous (nameless) and similar event-handing functions,
4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	11 one for each node. Often, :doc:`delegation` allows us replace a many
4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	12 similar functions by a single function.
11 ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	13
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	14 Defining a function
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	15 -------------------
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	16
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	17 When defining a function in JavaScript use
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	18
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	19 .. code-block:: javascript
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	20
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	21 var my_fn = function(arg1, arg2, arg3){
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	22 // Body of the function.
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	23 };
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	24
12 4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	25 as the template, where of course you get to choose the number and
11 ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	26 names of the parameters. Unlike Python, you can't provide default
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	27 values for the arguments, nor can you provide *\args** and
66 b76dbf891f88 functions.rst: Minor editorial changes. Jonathan Fine <jfine@pytex.org> parents: 12 diff changeset	28 *\\kwargs*. However, as we will see, there is the pseudo-variable
b76dbf891f88 functions.rst: Minor editorial changes. Jonathan Fine <jfine@pytex.org> parents: 12 diff changeset	29 arguments in JavaScript.
11 ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	30
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	31 This template can be adapted
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	32
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	33 .. code-block:: javascript
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	34
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	35 obj.my_fn = function(arg1, arg2, arg3){
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	36 // Body of the function.
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	37 };
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	38
66 b76dbf891f88 functions.rst: Minor editorial changes. Jonathan Fine <jfine@pytex.org> parents: 12 diff changeset	39 to define an attribute or method of an object. This is most commonly
b76dbf891f88 functions.rst: Minor editorial changes. Jonathan Fine <jfine@pytex.org> parents: 12 diff changeset	40 done when obj is a prototype.
11 ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	41
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	42 You can also put a function in an object literal, as in
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	43
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	44 .. code-block:: javascript
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	45
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	46 obj = {
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	47
66 b76dbf891f88 functions.rst: Minor editorial changes. Jonathan Fine <jfine@pytex.org> parents: 12 diff changeset	48 'my_fn': function(arg1, arg2, arg3){
11 ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	49 // Body of the function.
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	50 }
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	51 };
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	52
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	53 but this is often best avoided.
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	54
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	55 JavaScript provides another method (called function declaration)
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	56
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	57 .. code-block:: javascript
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	58
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	59 function my_fn(arg1, arg2, arg3){
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	60 // Body of the function.
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	61 };
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	62
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	63 which should (in the author's view) never be used. It has strange
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	64 properties [link].
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	65
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	66
12 4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	67 .. _calling-a-function:
4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	68
11 ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	69 Calling a function
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	70 ------------------
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	71
12 4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	72 There are four ways of calling a function in JavaScript. The
11 ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	73 difference involves :doc:`functions-and-this`, which we've not covered
12 4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	74 yet. In brief, the four forms are:
11 ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	75
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	76 .. code-block:: javascript
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	77
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	78 x = my_fn(a, b, c); // Simple function call.
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	79 x = obj.my_fn(a, b, c); // Method call.
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	80 x = my_fn.call(obj, a, b, c); // Explicit this call.
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	81 x = my_fn.apply(obj, [a, b, c]); // Explicit this apply.
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	82
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	83 For all forms of the function call, supplying the wrong number of
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	84 arguments does not raise an error. Instead, excess arguments are
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	85 ignored, and excess parameters are initialised to undefined.
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	86
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	87
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	88 Function call
12 4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	89 ^^^^^^^^^^^^^
11 ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	90
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	91 This is the simplest form of function call.
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	92
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	93 .. code-block:: javascript
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	94
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	95 x = my_fn(a, b, c);
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	96
12 4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	97 The this-object is set to the :doc:`global-object`, which causes a
66 b76dbf891f88 functions.rst: Minor editorial changes. Jonathan Fine <jfine@pytex.org> parents: 12 diff changeset	98 problem only if the body of the function refers to this. Many
b76dbf891f88 functions.rst: Minor editorial changes. Jonathan Fine <jfine@pytex.org> parents: 12 diff changeset	99 functions are intended to be used in this way.
11 ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	100
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	101
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	102 Method call
12 4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	103 ^^^^^^^^^^^
11 ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	104
12 4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	105 This is the usual, but not the most general, way of setting the this-object.
11 ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	106
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	107 .. code-block:: javascript
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	108
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	109 x = obj.my_fn(a, b, c); // Usual form.
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	110 x = obj['my_fn'](a, b, c); // Variant form.
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	111
12 4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	112 The two forms are completely equivalent. The this-object is set to
4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	113 the obj.
11 ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	114
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	115 The two following calls are always equivalent:
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	116
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	117 .. code-block:: javascript
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	118
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	119 x = a.b.c.d.e.my_fn(a, b, c);
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	120 tmp = a.b.c.d.e
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	121 x = tmp.my_fn(a, b, c);
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	122
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	123 Method call gotcha
12 4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	124 ^^^^^^^^^^^^^^^^^^
11 ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	125
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	126 In JavaScript the two following calls are rarely equivalent:
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	127
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	128 .. code-block:: javascript
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	129
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	130 x = obj.my_fn(a, b, c);
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	131 tmp = obj.my_fn
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	132 x = tmp(a, b, c);
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	133
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	134 whereas in Python they always are.
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	135
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	136 For JavaScript, in the first the this-object is obj while in the
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	137 second it is the global-object. For explanation see [link].
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	138
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	139 Explicit this-call
12 4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	140 ^^^^^^^^^^^^^^^^^^
4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	141
4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	142 Suppose obj is a JavaScript object. Then
11 ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	143
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	144 .. code-block:: javascript
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	145
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	146 x = my_fn.call(obj, a, b, c);
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	147
12 4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	148 is equivalent to
11 ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	149
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	150 .. code-block:: javascript
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	151
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	152 x = my_fn(a, b, c);
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	153
12 4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	154 except that the this-object is set to obj (rather than the global
4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	155 object). For more see [link].
11 ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	156
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	157 Explicit this-apply
12 4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	158 ^^^^^^^^^^^^^^^^^^^
4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	159
4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	160 Suppose obj is a JavaScript object. Then
11 ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	161
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	162 .. code-block:: javascript
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	163
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	164 x = my_fn.apply(obj, [a, b, c]);
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	165
12 4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	166 is equivalent to
11 ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	167
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	168 .. code-block:: javascript
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	169
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	170 x = my_fn(a, b, c);
ede8f282fb9f functions.rst: Good enough for the current draft. Jonathan Fine <jfine@pytex.org> parents: 6 diff changeset	171
12 4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	172 except that the this-object is set to obj. For more see [link].
4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	173
4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	174 Explicit this gotcha
4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	175 ^^^^^^^^^^^^^^^^^^^^
4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	176
4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	177 If obj is not a JavaScript object then in
4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	178
4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	179 .. code-block:: javascript
4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	180
4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	181 x = my_fn.call(obj, a, b, c);
4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	182 x = my_fn.apply(obj, [a, b, c]);
4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	183
4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	184 the this-object is set to the global object (which is probably not
4be9f1bf2fd3 Reviewed and revised existing pages, and added some new stub pages. Jonathan Fine <jfine@pytex.org> parents: 11 diff changeset	185 what you want). For more see [link].

Mercurial > js4py

annotate source/functions.rst @ 162:77e87f1b5811 core-javascript